Radar systems transmit electromagnetic radiation and analyze reflected echoes of returned radiation to determine information about the presence, position, and motion of objects within a scanned area. Conventional weapon locating systems include a radar system that can detect and track projectiles, such as artillery projectiles, to determine the location of the fired weapon. This determination can be based on an extrapolation of estimated state vectors, derived by radar tracking of a ballistic target, to a point of intersection. Identified coordinates associated with the intersection point approximate the location of the weapon that launched the projectile.
When the elevation angle of the bore of the fired weapon is small relative to the local earth tangent plane, conventional weapon locating systems are generally unable to accurately determine the location of the weapon. Such low angle trajectories produce exaggerated errors in the state vector estimates. As the angle of elevation approaches zero, the intersection point on the terrain becomes indeterminate. At low angle trajectories, weapon location determination is also limited because projectile detection and tracking by radar systems can be limited by impaired lines of sight, radar multipath echoes, and clutter. In addition, the short track life of near-in fire with low angle trajectories creates difficulties in discriminating false targets. When the location of the firing weapon cannot be accurately determined, the ability to return precision counter fire or launch rockets at the firing weapon is impaired.